U.S. Pat. No. 6,511,180 B2 relates to a method and a system for determining a refractive correction for a human eye and includes objective measurement of higher order wavefront errors and accurate estimation of the subjective refraction.
WO 02/083078 A2 relates to a method for determining an ocular refraction, the aim being to attain a desired quality with regard to a selected visual characteristic. To this end, wavefront errors are measured in order to objectively determine the status of the ocular refraction. It is stated that the visual quality of an accumulative result of the ocular refraction is among many different conditions of use. The desired visual quality can differ for various primary requirements of the individual patients. These various requirements can relate, for example, to night vision. Objective and subjective refraction measurements are carried out on test subjects in order to determine correlations that are later applied to new patients. There is no individual measurement. In order to achieve a desired visual quality, a refraction is measured, and the latter is described by a mathematical function. Thereafter, this mathematical function is optimized in order to improve the prescribed visual characteristic in the scope of the visual quality.